5 ms·

The crisis of American forensics

74 points by zeveb 9y ago

jernfrost 9y ago
Precedent is a terribly principle to apply to science. In fact it must be the worst possible way of approaching science. Science almost by definition is about challenging and upending established conventions and "truths". Imagine if we were to continue to treat desease spreading as a product of bad smell and insist on doing it rather than focus on hygiene because there is PRECEDENCE for doing so. head shaking
deleted 9y ago
[deleted]
asynchrony 9y ago
I suspect that in at least some cases when the actual perpetrator discovers that law enforcement has focused in on the incorrect suspect and is expending great resources to prove that suspect's guilt, they simply take their get out jail free card and move on. I have no background in psychology, but I'm confident that statistics will support that even the most deranged actors will be able to suppress their antisocial impulses to take advantage of such opportunities. Personally, I would rather have a statistical algorithm prioritize suspects than a human detective with a feeling (and the influence to set an entire law enforcement agency after a weak suspect).
- throwaway2048 9y ago
  Until your statistical algorithm decides that black=crime due to the data sets its been fed, and nobody dares question the wisdom of the computer. Before you reply that detectives might/would have done that anyways, the point is that at least that is identifiable and addressable, how do you determine how a neural net makes its decisions?
  - sovok_x 9y ago
    There are many algorithms already that render ANNs into decision trees and other interpretable forms. Nothing to fear here, citizen.
    - throwaway2048 9y ago
      show me some, that approach is at best experimental as far as I'm aware, and unable to create a 1:1 correspondence with how an ANN classifies. A far cry from "many algorithms" like its some kind of well established practice and fact.
      - sovok_x 9y ago
        https://arxiv.org/abs/1711.09784 https://arxiv.org/abs/1711.09784 https://arxiv.org/abs/1708.01785 https://arxiv.org/abs/1708.01785 https://arxiv.org/abs/1710.00935 https://arxiv.org/abs/1710.00935 https://arxiv.org/abs/1702.04595 https://arxiv.org/abs/1702.04595 https://arxiv.org/abs/1801.01693 https://arxiv.org/abs/1801.01693 https://arxiv.org/abs/1503.02531 https://arxiv.org/abs/1503.02531 https://arxiv.org/abs/1712.03781 https://arxiv.org/abs/1712.03781 https://arxiv.org/abs/1710.07535 https://arxiv.org/abs/1710.07535 https://arxiv.org/abs/1702.02540 https://arxiv.org/abs/1702.02540 https://arxiv.org/abs/1603.02518 https://arxiv.org/abs/1603.02518 http://ieeexplore.ieee.org/document/977279/ http://ieeexplore.ieee.org/document/977279/ etc It is kind of far cry from established practice but how far cry from established implementation are your fears of unintended abuse? It's not nearly at the point yet to be paranoid. Having bugs in ANN before debugging makes them no different from usual software that is already used in forensic research. And nobody in their right mind will deploy networks that impossible or prohibitively difficult to debug for any kind of critical tasks. Otherwise irrational people can abuse power even without any software or ANNs.
  - Sacho 9y ago
    > Before you reply that detectives might/would have done that anyways, the point is that at least that is identifiable and addressable I think you're handwaving the difficulty of identifying and addressing bias and discrimination. I'm not sure it's any easier to do for people than for computers. Computers have a huge advantage here because we can open up their brain and examine how they think, and once we create one that suits our tastes, we can replicate it faithfully. Humans are much more of a black box than a neural net would ever be.
    - deleted 9y ago
      [deleted]
  - maxerickson 9y ago
    A statistical model will tend to measure bias in the data. If some parameter is well correlated with the bias, the model will discount that parameter. It's not magic, it isn't going to just erase the bias, but a reasonable model will reduce bias rather than reinforcing it.
  - asynchrony 9y ago
    That's a very real danger. As much as I can side with the desire to have a human in the loop to observe the system, I'm not sure I trust any particular human to be free of bias or immune to emotional reactions that result in incorrect intuitions.
- bsder 9y ago
  > I have no background in psychology, but I'm confident that statistics will support that even the most deranged actors will be able to suppress their antisocial impulses to take advantage of such opportunities. You would be wrong. You have clearly never worked with people with dementia. Many forms of dementia impact your impulse control. Such people cannot control impulses--antisocial or not.
  - asynchrony 9y ago
    I was thinking more of high-functioning socio paths than people who have lost some mental capacity. I appreciate the benefit of your experience on the topic.
jstewartmobile 9y ago
Until DNA, forensics has always been pseudoscience voodoo. Detectives I've known guesstimated the fingerprint error rate to be much higher than 1 in 24--and fingerprints used to be the gold standard. I've even heard a few judges stress the importance of informing jurors before a trial on how most forensic evidence is nowhere near as solid as crime dramas make it out to be. These were sharp guys though, so that is probably not common practice.
- junkcollector 9y ago
  Conceptually, pattern matching isn't wrong. It's the implementation, presentation, and gross exaggeration of efficacy that is the real problem. DNA matching is still often pseudoscience voodoo the way it is used in courts for many of the same reasons that tooling marking is. Just look at Massachusetts, where they are having to retry 10's of thousands of cases because tests were botched by an malicious technician and then passed off in courts as foolproof even when the prosecution knew them to be suspect.
0xcde4c3db 9y ago
I think the Genrich case is just as much a story about prejudice against the mentally ill as it is a story about the failures of forensic science. > Martinez understands that Genrich comes off as “weird.” But, he insists, “He didn’t have a violent bone in his body. He never hurt anybody. He was the one getting hurt.” As far as I've read about it, this is pretty much the norm for people with serious mental illness. They're believed to be aggressors, but in reality are vastly more likely to be victims because their alienation and unstable lives render them highly vulnerable to the tactics of abusers (which are often similar to the tactics that law enforcement officers use against suspects). People tend to assume they're lying or delusional when they tell anyone what happened.
logfromblammo 9y ago
It must be stressful knowing your entire profession is BS with a glossy veneer over it, and the walls could all come crashing down in an instant. In some ways, we have come a long way from employing ducking stools to detect witches, but in other ways, we have not advanced at all.

74 points by zeveb 9y ago

Precedent is a terribly principle to apply to science. In fact it must be the worst possible way of approaching science. Science almost by definition is about challenging and upending established conventions and "truths". Imagine if we were to continue to treat desease spreading as a product of bad smell and insist on doing it rather than focus on hygiene because there is PRECEDENCE for doing so. head shaking

deleted 9y ago

[deleted]

asynchrony 9y ago

I suspect that in at least some cases when the actual perpetrator discovers that law enforcement has focused in on the incorrect suspect and is expending great resources to prove that suspect's guilt, they simply take their get out jail free card and move on. I have no background in psychology, but I'm confident that statistics will support that even the most deranged actors will be able to suppress their antisocial impulses to take advantage of such opportunities. Personally, I would rather have a statistical algorithm prioritize suspects than a human detective with a feeling (and the influence to set an entire law enforcement agency after a weak suspect).

throwaway2048 9y ago
Until your statistical algorithm decides that black=crime due to the data sets its been fed, and nobody dares question the wisdom of the computer. Before you reply that detectives might/would have done that anyways, the point is that at least that is identifiable and addressable, how do you determine how a neural net makes its decisions?
- sovok_x 9y ago
  There are many algorithms already that render ANNs into decision trees and other interpretable forms. Nothing to fear here, citizen.
  - throwaway2048 9y ago
    show me some, that approach is at best experimental as far as I'm aware, and unable to create a 1:1 correspondence with how an ANN classifies. A far cry from "many algorithms" like its some kind of well established practice and fact.
    - sovok_x 9y ago
      https://arxiv.org/abs/1711.09784 https://arxiv.org/abs/1711.09784 https://arxiv.org/abs/1708.01785 https://arxiv.org/abs/1708.01785 https://arxiv.org/abs/1710.00935 https://arxiv.org/abs/1710.00935 https://arxiv.org/abs/1702.04595 https://arxiv.org/abs/1702.04595 https://arxiv.org/abs/1801.01693 https://arxiv.org/abs/1801.01693 https://arxiv.org/abs/1503.02531 https://arxiv.org/abs/1503.02531 https://arxiv.org/abs/1712.03781 https://arxiv.org/abs/1712.03781 https://arxiv.org/abs/1710.07535 https://arxiv.org/abs/1710.07535 https://arxiv.org/abs/1702.02540 https://arxiv.org/abs/1702.02540 https://arxiv.org/abs/1603.02518 https://arxiv.org/abs/1603.02518 http://ieeexplore.ieee.org/document/977279/ http://ieeexplore.ieee.org/document/977279/ etc It is kind of far cry from established practice but how far cry from established implementation are your fears of unintended abuse? It's not nearly at the point yet to be paranoid. Having bugs in ANN before debugging makes them no different from usual software that is already used in forensic research. And nobody in their right mind will deploy networks that impossible or prohibitively difficult to debug for any kind of critical tasks. Otherwise irrational people can abuse power even without any software or ANNs.
- Sacho 9y ago
  > Before you reply that detectives might/would have done that anyways, the point is that at least that is identifiable and addressable I think you're handwaving the difficulty of identifying and addressing bias and discrimination. I'm not sure it's any easier to do for people than for computers. Computers have a huge advantage here because we can open up their brain and examine how they think, and once we create one that suits our tastes, we can replicate it faithfully. Humans are much more of a black box than a neural net would ever be.
  - deleted 9y ago
    [deleted]
- maxerickson 9y ago
  A statistical model will tend to measure bias in the data. If some parameter is well correlated with the bias, the model will discount that parameter. It's not magic, it isn't going to just erase the bias, but a reasonable model will reduce bias rather than reinforcing it.
- asynchrony 9y ago
  That's a very real danger. As much as I can side with the desire to have a human in the loop to observe the system, I'm not sure I trust any particular human to be free of bias or immune to emotional reactions that result in incorrect intuitions.
bsder 9y ago
> I have no background in psychology, but I'm confident that statistics will support that even the most deranged actors will be able to suppress their antisocial impulses to take advantage of such opportunities. You would be wrong. You have clearly never worked with people with dementia. Many forms of dementia impact your impulse control. Such people cannot control impulses--antisocial or not.
- asynchrony 9y ago
  I was thinking more of high-functioning socio paths than people who have lost some mental capacity. I appreciate the benefit of your experience on the topic.

jstewartmobile 9y ago

Until DNA, forensics has always been pseudoscience voodoo. Detectives I've known guesstimated the fingerprint error rate to be much higher than 1 in 24--and fingerprints used to be the gold standard. I've even heard a few judges stress the importance of informing jurors before a trial on how most forensic evidence is nowhere near as solid as crime dramas make it out to be. These were sharp guys though, so that is probably not common practice.

junkcollector 9y ago
Conceptually, pattern matching isn't wrong. It's the implementation, presentation, and gross exaggeration of efficacy that is the real problem. DNA matching is still often pseudoscience voodoo the way it is used in courts for many of the same reasons that tooling marking is. Just look at Massachusetts, where they are having to retry 10's of thousands of cases because tests were botched by an malicious technician and then passed off in courts as foolproof even when the prosecution knew them to be suspect.

0xcde4c3db 9y ago

I think the Genrich case is just as much a story about prejudice against the mentally ill as it is a story about the failures of forensic science. > Martinez understands that Genrich comes off as “weird.” But, he insists, “He didn’t have a violent bone in his body. He never hurt anybody. He was the one getting hurt.” As far as I've read about it, this is pretty much the norm for people with serious mental illness. They're believed to be aggressors, but in reality are vastly more likely to be victims because their alienation and unstable lives render them highly vulnerable to the tactics of abusers (which are often similar to the tactics that law enforcement officers use against suspects). People tend to assume they're lying or delusional when they tell anyone what happened.

logfromblammo 9y ago

It must be stressful knowing your entire profession is BS with a glossy veneer over it, and the walls could all come crashing down in an instant. In some ways, we have come a long way from employing ducking stools to detect witches, but in other ways, we have not advanced at all.